At the late—symptomatic stage of the disease (days four to five p.i.)in which the mice infected with either of the strains showed signs of morbidity (i.e., weight loss and ruffled fur, Figure 1A), a set of 11 genes were significantly upregulated in the VACV-Wyeth-infected group compared to the VACV-WR-infection while other eight genes were significantly elevated in the VACV-WR-infected brains as compared to the VACV-Wyeth-infection (Figure 7B). The gene discussed is FURIN; the disease is infection.